Gearing arrangement for supercharged power plant



Oct. 2, 1951 s CQULING 2,570,101

GEARING ARRANGEMENT FOR SUPERCHARGED POWER PLANT Filed Jan. 14, 1947 inventor. Stephen A. Co uling b5 His Attorney.

Patented Oct. 2, 1951 GEARING ARRANGEMENT FOR SUPER- CHARGED POWER'PLANT 1 Ste hen A. Couling, Rugby, England, assignor to General Electric Company, a corporation of New York Application January 14. 1947. Serial No. 722,048

In Great Britain February13, 1942 Section 1, Public Law 690, August s'. 1945 Patent expires February 13, 1962 I This invention relates to a composite powerplant comprising a gas turbine associated with an internal combustion engine for utilizing the exhaust gases from the engine, as well as to drive a supercharger or to permit the engine to assist the turbine in driving the supercharger. Such a powerplant has come to be knownto the aviation industry in the United States as a compound engine, and is particularly attractive for application to aircraft propulsion.

An object of the invention is to provide an improved supercharged compound engine so arranged that when supercharging is not required, the energy recovered from the engine exhaust gases is returned to the engine crankshaft and is thus employed continuously, so that maximum overall thermal efiiciency is obtained.

Another object of the invention is to provide a supercharging arrangement whereby one stage of the supercharger can be driven at different speeds.

A further object is to provide means for driving both stages of a two-stage supercharger simultaneously at different speeds.

Other objects and advantages will be apparent from the following description taken in connection with the accompanying .drawing, in which the single figure is a View in elevation, partly sectioned, of a powerplant embodying this invention,

Referring now to the accompanying drawing, a reciprocating internal combustion engine is indicated diagrammatically at 5, having a plurality of cylinders 6. A combustible mixture is supplied to the cylinders by an intake manifold 1 through branch conduits 8, and the resulting products of combustion exhaust through stacks 9 to a manifold I0.

Arranged parallel with the engine crankshaft II are two countershafts, one having separate portions I2, I3, I4, and the other being divided into portions I5 and I5, all of which are supported by suitable bearings I1. Shaft portions I2, I3, I4 are arranged to be selectively connected together by suitable clutches I8, I9 while shaft portions I5, Iii are adapted to be connected in a similar manner by clutch 20. A gas turbine 2| is mounted on shaft I2 and has a nozzlebox 22 supplied with operating fluid from exhaust mani fold I0. Secured to the end of shaft i2 is a pinion gear 23, which engages a gear 24 mounted on crankshaft II, gear 24 in turn engaging a pinion 25 secured to shaft I5. Pinion 25 differs in the number of its teeth from pinion 23 so that the speed ratios of these pinions to gear 24 are 2 Claims. (01. 60-13) I 2 V different. Specifically, gear 25 may be larger than gear 23, so that shaft I5 will rotate slower than shaft I2 relative to the crankshaft speed. Secured to shaft I3 is a pinion 26 which engages an idler'gear 21, supported by bearings 28. Gear 21, in turn. engages a pinion 29 secured to the end of shaft I6. I

Mounted on shaft I6 is an impeller 30 of a centrifugal compressor 3|, having an inlet conduit 32 and an outlet conduit 33. Conduit 33 communicateswith the engine intake manifold 1 by means of a conduit 34.

With the'power transmission described, supercharger 3I .may beoperated alone to provide single stage supercharging, or it may be used as the second stage of a two-stage supercharging system. To this end inlet conduit 32 of supercharger 3| communicates with the outlet of another compressor 35 having an impeller 36 carried by shaft I4 and anair-intake annulus 31. In order that compressor 3| may receive air directly when operating alone, conduit 32 may be provided with an atmospheric vent 32c containing a valve .38, which may be controlled manually orb-automatically in any one of several ways.-,

' The operation of my powerplant is as follows:

The turbine 2I is at all times geared directly to the engine crankshaft I I through pinion 23 and gear wheel 24. To employ compressor 31 as a, single stage supercharger, valve 38 is first actuated to open vent 32a to atmosphere. Clutch 20 is then engaged, and clutches I8 and [[9 disengaged, to Connect shafts I5, I6, whereupon the impeller 30 is driven, at a comparatively low speed, through gear 24 and pinion 25.

To obtain a higher speed ratio for the impeller 30, clutch 20 is disconnected and clutch I8 is engaged to connect shafts I2 and I3. As already indicated, gearing 23, 24, 25 may be arranged so that the ratio of gears 23, 24 is greater than that of gears 25, 24 so that shaft I2 rotates at a speed higher than that of shaft I5. Thus when impeller 30 is driven from shaft I2 through clutch I8, pinion 26, idler 21, and pinion 29, it rotates at a speed greater than that attained by the impeller when the drive is from shaft I5 through clutch 20 and a higher degree of supercharging is obtained. It will be apparent that the ratio of gears 26, 21, 29 must not be equal to that of gears 23, 24, 25 if the important advantage of different possible speeds of operation of impeller I3 is to be realized. Aside from this consideration, the ratio of gears 26, 21, 29 as compared with gears 23, 24, 25 is not critical and in practicing the invention these ratios may be varied to match the compressor characteristics.

When a still greater amount of supercharging is required, valve 38 is positioned to close vent 32a and clutch I8 is disengaged. Then clutches, 1,

l9 and 2B are engaged to connect shafts l3, l4 and shafts l5, l6 respectively, so that both compressors 35 and 3| will be driven in series. With this arrangement the air discharged from supercharger 35 passes through conduit 32 to supercharger 3|, thence through conduits 33, 34 to the intake manifold I of engine 5.

It will be'seen that in this powerplant the gas turbine is always utilized to return energy to the engine crankshaft. By suitable design of the gearing overspeeding of the turbine wheel can be prevented, since the engine is operated at a controlled speed and, the turbine wheel is geared thereto at a fixed speed ratio. A further advantage is that the energy for supercharging can be obtained either from the turbine-engine combination or from the reciprocating engine alone. Also provision is made for low and high speeds of the primary supercharger and for the two-stage compressor operation when still more supercharging is required.

While a particular embodiment of the invention has been illustrated and described, it will be obvious to those familiar with the'art that various changes and modifications may be made without departing from the invention; and it is intended'to cover in the appended claims all such changes and modifications as come within the true spirit and scope of the invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. In an engine-turbine-compressor unit, the combination of a reciprocating internal combustion engine, a first countershaft divided into a first shaft portion carrying a gas turbine, rotor, a second shaft portion, first clutch means for selectively coupling said first and second shaft portions, and a third shaft portion carrying a first compressor rotor, second clutch means adapted to selectively couple said second and third shaft portions, a second countershaft divided into a fourth shaft portion and a fiftl shaft portion carrying a second compressor rotor, gearing connecting said first and fourth shaft portions at fixed speed ratios to the engine crankshaft, other gearing connecting said second and fifth shaft portions at a fixed speed ratio, third clutch means for selectively coupling said fourth and fifth shaft portions, hot gas conduit means connected to supply combustion products from the engine to the gas turbine, air conduit means connecting said first and second compressors in series and to the engine, and atmospheric vent means in said air conduit intermediate the first and second compressors, whereby said first compressor rotor can be driven to either of two gear trains for single stage supercharging and both compressors can be operated in series for twostage supercharging.

2. In an engine-turbine-compressor unit, the combination of a reciprocating internal combustion engine, a first countershaft divided intoa first shaft portion carrying a gas turbine rotor, a second shaft portion, clutch means for selectively coupling said second shaft portion tosaid first portion, and a third shaft portion carrying a first compressor rotor, second clutch means for selectively coupling said third shaft portion to the second shaft portion, a second countershaft divided into a fourth shaft portion and a fifth shaft portion carrying a second compressor rotor, third clutch means for selectively coupling said fifth shaft portion to the fourth shaft portion, gearing connecting said first and fourth shaft portions at fixed speed ratios to the engine crankshaft, other gearing connecting said second and fifth shaft portions at a fixed speed ratio, hot gas conduit means connected to supply combustion products from the engine to the gas turbine whereby the energy in the engine exhaust is utilized at all times, and air conduit means connecting said first and second compressors in series and to the engine, whereby said first compressor rotor can be driven through either of two gear trains for single stage supercharging and both compressors can be operated in series for two stage supercharging,

' STEPHEN A. COULING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,020,224. Waseige Nov. 5, 1935 2,065,955 Waseige Dec. 29, 1936 2,173,595 Schiitte Sept. 19, 1939 FOREIGN PATENTS Number Country Date 398,902 Germany July 16, 1924 

